The invention relates to a surgical instrument having a tubular shaft with working elements arranged at the distal end thereof, at least one of the elements capable of being spread apart. The working elements are connected via an actuator element with a handle arranged at the proximal end of the shaft for opening and closing the working elements. The instrument further comprises a hollow channel passing through the interior of the instrument, into which at least one further instrument may be inserted.
A surgical instrument of the above type is disclosed in the international patent application WO 96 22 056. In an embodiment of the multifunctional surgical instrument disclosed there, the working elements are both formed as spreadable jaw portions. In the closed condition, the jaws substantially close the distal end of the hollow channel, where only a small semi-circular recess is provided at a central portion of each jaw. A small opening results through which a thin cannula of a syringe may pass, after having been inserted from the proximal end into the central hollow channel of the tubular shaft.
In recent times, minimally invasive surgery has become widely Employed and it is common to observe procedures with surgical instruments inside the body with an endoscope. These instruments are introduced into the body by means of a trocar, where relatively small incisions are required initially to introduce the trocar into the body. If a surgical instrument, for example surgical scissors, are introduced at a different location than the endoscope for observing the cutting procedure, then two incisions are necessary.
In these types of operations, one strives to make as few incisions as possible. It is thus known to introduce several instruments into the body through one incision. The shaft or tube of the surgical instrument then is disposed adjacent to the tube of the endoscope. The instruments normally have at least approximately a circular cross section, as does the outer shaft encompassing the two instruments, i.e. the shaft through which the two instruments adjacent to one another are introduced into the body through the single incision. Consequently, only about half of the lumen of the outer shaft is used. Thus with a certain cross sectional dimension of the surgical instrument, the diameter of the outer shaft must be unnecessarily large. Even if a portion of the remaining space can be used as a flushing channel or for other purposes, the available space of the lumen is always insufficiently used.
The object of the present invention is to avoid the above drawbacks and provide a surgical instrument or an instrument system, by which the outer tube diameter remains small even when an additional instrument apart from a surgical instrument is to be passed through the same incision.
According to the present invention, the hollow channel has a cross section corresponding approximately to the inner clearance diameter of the tubular shaft, and the working elements are configured such that they do not pass into the cross section of an imaginary distal prolongation of the hollow channel in said tubular shaft in either closed or opened condition of said working elements.
The feature has the advantage that the entire interior space of the tubular shaft is available for introduction of a further instrument. At the most, the available cross section is reduced by the usual rod-shaped actuator element, assuming it is passed through the interior of the instrument.
By configuring the working element so as not to enter into the space in opened or closed condition, the full cross sectional area remains available in all operational states or conditions of the working elements. For example it is possible to introduce an endoscope through the continuous hollow channel, with which the manipulations of the working elements can be visually observed. As the working elements do not extend into the continuous hollow space, one can always observe procedures through the centrally introduced endoscope, for example when introducing the instrument with closed jaws. One can also then observe the manipulations of the working elements after having been inserted into the body.
Depending on the given purpose, the working elements can be variously configured, for example for the purpose of grasping and/or cutting, for laying tissue open or the like. Since the entire cross section of the tubular shaft is available as a hollow space, an endoscope with sufficient light intensity and visibility can be employed with relatively small diameter surgical instruments.
The hollow channel can also be employed as a sectioning and/or flushing channel. The combination of a sectioning/flushing channel with an endoscope is also possible, namely when the outer diameter of the endoscope shaft is smaller than the inner diameter of the hollow channel. Fluids or gaseous media can then be supplied or discharged through the intermediate space about the endoscope.
The working elements can also be provided as spreading elements, where other grasping or cutting instruments can then be passed through the hollow channel when the elements are separated.
The construction of the instruments within one another is very slender and as a particular advantage it is emphasized that the functionality of one instrument is not impaired by the other instrument.
In a further embodiment of the present invention, the working elements arranged at the distal end project in one working position as an extension of the wall of the tubular shaft. The advantage in this position is that the surgical instrument takes on the form of a tube in the region of the shaft and the working elements, which can be passed through a trocar for in-sertion into the body, so that a particularly space-saving con-figuration results.
In a further embodiment of the present invention, the working elements themselves have the form of a tube or tube section. The advantage is that the working elements themselves have a large cross section, but do not extend laterally beyond the shaft while allowing a maximal inside free width in the interior of the hollow channel. Thus a maximal inner hollow space is available combined with a slender construction of the surgical instrument and maximal stability of the working elements.
In a further embodiment of the present invention, the at least one actuator element is also formed to be of tubular shape. The advantage is that the actuator element passed through the interior of the instrument represents the least possible impairment in the hollow channel. The actuator element essentially transmits compression or tensile forces, so that the tubular geometry is ideal for transmitting high forces with the thinnest wall thicknesses. The tubular actuator element can also be configured such that it surrounds the hollow space.
In a further embodiment of the present invention, the actuator element comprises recesses acting as guide slots or curves, in which guide pins of the working elements engage. The advantage is that the engagement between the actuator element with the working elements is accomplished with means extending in the circumferential direction or the longitudinal direction of the actuator element, so that the inner hollow channel is not obstructed by these components.
In a further embodiment of the present invention, the actuator element engages the working elements through pivotal intermediate means. The advantage is that extended positions of the pivotal means are possible, which are displaced in the most spacesaving manner, whether when introducing the instrument itself through a trocar or when inserting a further instrument into the inner hollow space.
In a further embodiment of the present invention, the actuator element engages with the working elements through flexible intermediate means. This has the advantage that slender or narrow components are provided which do not enlarge the construction or obstruct the inner hollow channel.
In a further embodiment of the present invention, the working elements are mounted to the shaft by pivot joints. The advantage is that the pivotal mounting on the shaft achieves sufficient stability of the working elements and still saves space.
In a further embodiment of the present invention, the working elements are mounted on the shaft through flexible bands or foil joints. The advantage is that a flat joint construction, narrow in radial direction is possible. Again, sufficient stability is provided and neither the construction width is enlarged nor is the inner hollow channel obstructed.
In a further embodiment, the mounting is provided to have the broadest possible base, preferably approximately the outer diameter of the tubular shaft. This can be achieved for example in that the base is formed as half-rings with two diametrically opposite securement points, on which the working elements or the jaws are arranged.
In a further embodiment of the present invention, the working elements are configured as two jaws of a scissors or a grasping tongs. The advantage is that the surgical instrument is formed as a frequently used instrument with which very strong forces must be transmitted for grasping or cutting procedures. Due to the mentioned configuration, these procedures can be carried out without problem in the slender design while leaving a large portion of the hollow channel free.
In a further embodiment of the present invention, the jaws are formed as tubular sections extending in circumference a little more than 90xc2x0 and lying adjacent to one another. Their opposing edges are arranged to pass one another in scissor-like manner. This preferred embodiment has the advantage that the jaws neither extend beyond the width of the shaft at its outer periphery, nor is the inner hollow channel impaired. Thus, a maximal inner channel space is available with minimal shaft diameter. The channel completely passes through the shaft so that instruments can be inserted beyond the jaw portion, independent of whether these are opened or closed.
It will be understood that the above-mentioned features and those to be discussed below are not only applicable in the given combinations, but may be present in other combinations or taken alone without departing from the scope of the present invention.